Remove dead code related to media device enumerations and monitoring.

content/renderer/media/rtc_peer_connection_handler_unittest.cc

Index: content/renderer/media/rtc_peer_connection_handler_unittest.cc
diff --git a/content/renderer/media/rtc_peer_connection_handler_unittest.cc b/content/renderer/media/rtc_peer_connection_handler_unittest.cc
index 568f6e5d5a3508b4f6510a8453739fc9cbf42714..8cb640a16abf5c8ccc504536334e47e353d7819a 100644
--- a/content/renderer/media/rtc_peer_connection_handler_unittest.cc
+++ b/content/renderer/media/rtc_peer_connection_handler_unittest.cc
@@ -192,9 +192,9 @@ class MockPeerConnectionTracker : public PeerConnectionTracker {
 
 class MockRTCStatsReportCallback : public blink::WebRTCStatsReportCallback {
  public:
-  MockRTCStatsReportCallback(std::unique_ptr<blink::WebRTCStatsReport>* result)
-      : main_thread_(base::ThreadTaskRunnerHandle::Get()),
-        result_(result) {
+  explicit MockRTCStatsReportCallback(
+      std::unique_ptr<blink::WebRTCStatsReport>* result)
+      : main_thread_(base::ThreadTaskRunnerHandle::Get()), result_(result) {
     DCHECK(result_);
   }
 
@@ -291,7 +291,7 @@ class RTCPeerConnectionHandlerTest : public ::testing::Test {
         new ProcessedLocalAudioSource(
             -1 /* consumer_render_frame_id is N/A for non-browser tests */,
             StreamDeviceInfo(MEDIA_DEVICE_AUDIO_CAPTURE, "Mock device",
-                             "mock_device_id", "mock_group_id",
+                             "mock_device_id",
                              media::AudioParameters::kAudioCDSampleRate,
                              media::CHANNEL_LAYOUT_STEREO,
                              media::AudioParameters::kAudioCDSampleRate / 100),